PLATTSBtJRG. 107 PLAITEN. lowing year. Oflf 'akour Island, near by, on Oc- tober 11, 1776, occurred tbe first naval battle ever fought between British and American tleets, Ben- edict Arnold (q.v. ) being in command of the lat- ter and Sir Guy Carleton of the former. Arnold was defeated. During the War of IS 12 Platts- burg was the headquarters of the United States forces on the northern frontier, and on Septem- ber 11, 1814, in Plattsburg Bay, Commodore ilc- Donough defeated a British fleet in the famous battle of Lake Champlain (see Champlain), while on the land General JIacomb repulsed a .superior British force. In 1849 and again in 1867 Plattsburg suffered severely from fire, the greater part of the business portion being de- stroved each time. Consult Palmer, History of Plaitsburgh (Plattsburgh. 1S77). PLATTSBURG BARRACKS. A United States military post, established in 1838 and occupying a reservation of 670 acres in extent, on the west side of Lake Champlain, one mile from Plattsburg, X. Y., which is the post-ofiSce and telegraph station. The post has quarters for a regiment of infantry. United States troops were first stationed on the ground in 1812. PLATTS'MOUTH, A city and the county- seat of Cass County, Xeb., 21 miles south of Omaha ; on the ilissouri River at the mouth of the Platte, and on the Missouri Pacific and the Chicago, Burlington and Quincy railroads (ilap: Nebraska, J 2). It has a public library; and among its finest buildings are the court-house, opera house, and the high school. The industrial establishments include the Burlington Railroad .shops, brick and terracotta works, and cigar factories. There is considerable trade with the tributary region, which is interested mainly in agriculture and stock-raising. Plattsmouth is governed by a mayor, elected biennially, and a unicameral council. Population, in IS'JO, 8392; in 1900, 49G4. PLATYCERAS, pla-tis'er-os (Xeo-Lat., from Gk. jrXoTi5s, platiis. flat, broad -f x^pas, keras, horn ) . A genus of fossil snail shells of the gastro- pod family Capulidae, found in rocks of Upper Cambrian to Triassic age. They are shaped some- what like a liberty cap with the apex of the shell enrolled in a close spiral of small size and with the outer or body whorl of the shell rapidly enlarging to an irregularly expanded aperture. Platyceras is most abundant in the Niagara, the Devonian, and the Subearboniferous formations, and the genus is more or less an index fossil of Devonian age. The genus Orthonychia includes straight or slightly rounded platycerid shells of vSilurian to Carboniferous age. Consult : Keyes. '"The Platyceras Group of Paleozoic Gastropods," in American Geolofiiit. vol. x. (Minneapolis, 1892) ; "Attachment of Platyceras to Palaeocri- noidea. and Its Effect in Modifying the Form of the Shell," in Proceediiifis of the American Philo- sopliical Societfi. vol. xxv. (Philadelphia, 1888). PLAT'YHELMIN'THES (Xeo-Lat. nom. pi., from Gk. TrXaris. phiti/s. flat, broad -f Vfuvs, helm ins, worm), or Pl.toda. A phylum of in- vertebrate animals (flatworms), easily recognized by the absence of a body-cavity and anus. There is no blood system, the results of digestion being carried to the dift'erent parts of the body by branches of the intestine. The body is flattened dorsoventrally. so that it is often thin and leaf- like. The surface is covered with cilia in most Vol. XVI.— 8. of the free-living forms, but in parasitic forms is usually smooth and somewhat chitinous. The muscular system is well developed and remark- ablj- complex, so that almost any sort of move- ments are jjossible to these worms. The digestive system is usually very well developed and highly varied, but in some forms is wholly wanting. The nervous system consists of a ganglion above the a?sophagus, and two lateral nerve cords, con- nected by transverse commissures. Other longi- tudinal trunks are sometimes present, and rarely the transverse commissures are wanting. A very characteristic and remarkable set of fine tubes ramifies through the body and apparenth- serves as an excretory system. Sense organs of vari- ous kinds occur in the free-living forms, but are usually wanting in those which are parasitic. Occu])ying a large part of the body, and often nearly the whole space inside the skin, are the reproductive organs, and the fertilization of the egg is in almost all cases internal. The Tur- bellaria are hermaphroditic. The eggs are very numerous, provided with considerable yolk and covered by a shell, but some planarians multiply by fission, and when cut in pieces each piece may eventually become a well-formed planarian. The young undergo a metamorphosis and develop- ment sometimes very complex. The phy- lum is usually divided into three classes: (1) Turbellaria, free-living flatworms, with the sur- face ciliated; (2) Trematoda, parasitic, usually leaf-like, flatworms having a well-developed di- gestive system; (3) Cestoda. the tapeworms, usually elongated, jointed, and without a diges- tive system. Consult Parker and Haswell, Text- hook of Zoology (New York, 1897). See Flat- WOBil ; CE^STODA ; TrEMATODA. PLAT'YRHIIfl. The American monkeys. See Moxi'LEY. PLAT'YSTRO'PHIA (Neo-Lat. nom. pi., from Gk. vXarm, platys, broad, flat -- aTpb(j>ioi', strophion, band). A hinged brachiopod very abundant and eminently characteristic of the Middle Ordovician formations, of which it is a well-known index fossil. Its shell is transversely elongated, with a long straight hinge line and low hinge areas. The convex valves are of about equal size, and their surfaces are marked by a number of strong angular radiating folds. Two species, Platystrophia lynx and bilorata. with numerous varieties, are common in the Trenton and Cincinnati groups of North America, and in equivalent strata of Europe and elsewhere. This genus was originally included under Orthis. PLAUEN, plou'en. A town of Saxony. Ger- many, on the A"hite Elster, 21 miles southwest of Zwickau ( Map : Germany, E 3 ) . Most of its public buildings are modern. Among the most noteworthy are the castle, dating from the seven- teenth century, the Eathaus, and the theatre. The educational institutions include a giunasium, a realschule, a seminary for teachers, and a niuu- ber of special schools. Plauen occupies a promi- nent place among the manufacturing cities of Germany, being the chief centre for the produc- tion of white cotton goods, namely lace curtains, muslin, cambric, mull, batiste, various embroid- ered goods, etc. It also manufactures machinery, safes, pianos, paper, beer, etc. The population of the town increased from 47.007 in 1890 to 73.891 in 1000. The inhabitants are principally Prot- estants. The manufacturing of white goods was
